Collisions and Change in Momentum

Click For Summary

Homework Help Overview

The discussion revolves around a problem in the context of collisions and change in momentum, specifically involving a ball colliding with a wall and reversing direction.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants explore the calculation of initial and final momentum, questioning the signs and direction of momentum change. There is an attempt to clarify the difference between initial and final momentum values.

Discussion Status

The discussion is active, with participants providing calculations and questioning the implications of their results. Some guidance has been offered regarding the correct approach to finding the change in momentum.

Contextual Notes

Participants are navigating the importance of signs in momentum calculations and the implications of directionality in their results.

jabbie3
Messages
19
Reaction score
0

Homework Statement



A ball of mass 4.7 kg moving with speed of 1.9 m/s in the x-direction hits a wall and bounces back with the same speed in the -x-direction. What is the change of momentum of the ball? And in what direction?

Homework Equations



p=mv

The Attempt at a Solution



P=mv
P=4.7*1.9
P=8.93
 
Physics news on Phys.org
So what is the initial momentum?

What is the final momentum?

What is the difference?
 
The initial is 8.93 and the final is -8.93..so total momentum is 0? In what direction?
 
Try again using pf - pi to find the difference.
 
jabbie3 said:
The initial is 8.93 and the final is -8.93..so total momentum is 0? In what direction?

Sorry, signs matter.

Initial momentum = P
Final momentum = -P

Final - initial = Δ = (-P) - P = -2P

Negative because Δx/Δt is toward -x.
 

Similar threads

  • · Replies 13 ·
Replies
13
Views
1K
Replies
9
Views
4K
Replies
1
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 9 ·
Replies
9
Views
1K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 19 ·
Replies
19
Views
3K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 12 ·
Replies
12
Views
2K